AWS Certified Solutions Architect – Associate (SAA-C03)Design Cost-Optimized ArchitecturesEasy
A global software company provides a SaaS application hosted on AWS. They are launching a new feature that uses a data processing pipeline running on EC2 instances. This pipeline can tolerate occasional interruptions and has flexible start and end times, but needs to process large amounts of data as cost-effectively as possible. Which EC2 purchasing option offers the greatest cost savings for this workload?
- ASpot Instances
- BReserved Instances
- COn-Demand Instances
- DDedicated Hosts
Show answer & explanationAnswer & explanation
Correct answer: A. Spot Instances
Spot Instances offer significant discounts (up to 90% off On-Demand prices) for unused EC2 capacity. Since the data processing pipeline 'can tolerate occasional interruptions' and has 'flexible start and end times', Spot Instances are the most cost-effective choice.
Why the other options are wrong
- B. Reserved Instances provide discounts for committed usage but are best for steady-state, non-interruptible workloads, and the discount is less than Spot for interruptible workloads.
- C. On-Demand Instances provide maximum flexibility but are the most expensive option, not suitable for 'greatest cost savings'.
- D. Dedicated Hosts provide physical EC2 servers for license compliance but are generally more expensive than On-Demand and do not offer cost savings for a flexible, interruptible workload.
EC2 Spot Instances
EC2 Spot Instances allow you to bid for unused EC2 capacity at significantly reduced prices, suitable for fault-tolerant workloads.
- Up to 90% savings compared to On-Demand prices.
- Instances can be interrupted by AWS with a two-minute warning.
- Ideal for batch processing, data analytics, and other flexible workloads.
- Not suitable for mission-critical, non-interruptible applications.
Memory trick: Spot the Savings, Skip the Stress (of high cost).